From 92bfeeca1bdc71cada715993f669e2c1a5693b74 Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Wed, 13 May 2015 13:50:22 +0200
Subject: [PATCH] No need to release lock and acquire again when allocate
 normal size.

Motiviation:

When tried to allocate tiny and small sized and failed to serve these out of the PoolSubPage we exit the synchronization
block just to enter it again when call allocateNormal(...).

Modification:

Not exit the synchronized block until allocateNormal(...) is done.

Result:

Better performance.
---
 .../src/main/java/io/netty/buffer/PoolArena.java   | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/buffer/src/main/java/io/netty/buffer/PoolArena.java b/buffer/src/main/java/io/netty/buffer/PoolArena.java
index a9ae9ddc26..6275f9d9e6 100644
--- a/buffer/src/main/java/io/netty/buffer/PoolArena.java
+++ b/buffer/src/main/java/io/netty/buffer/PoolArena.java
@@ -144,8 +144,8 @@ abstract class PoolArena<T> {
                 table = smallSubpagePools;
             }
 
+            final PoolSubpage<T> head = table[tableIdx];
             synchronized (this) {
-                final PoolSubpage<T> head = table[tableIdx];
                 final PoolSubpage<T> s = head.next;
                 if (s != head) {
                     assert s.doNotDestroy && s.elemSize == normCapacity;
@@ -154,21 +154,25 @@ abstract class PoolArena<T> {
                     s.chunk.initBufWithSubpage(buf, handle, reqCapacity);
                     return;
                 }
+                allocateNormal(buf, reqCapacity, normCapacity);
+                return;
             }
-        } else if (normCapacity <= chunkSize) {
+        }
+        if (normCapacity <= chunkSize) {
             if (cache.allocateNormal(this, buf, reqCapacity, normCapacity)) {
                 // was able to allocate out of the cache so move on
                 return;
             }
+            synchronized (this) {
+                allocateNormal(buf, reqCapacity, normCapacity);
+            }
         } else {
             // Huge allocations are never served via the cache so just call allocateHuge
             allocateHuge(buf, reqCapacity);
-            return;
         }
-        allocateNormal(buf, reqCapacity, normCapacity);
     }
 
-    private synchronized void allocateNormal(PooledByteBuf<T> buf, int reqCapacity, int normCapacity) {
+    private void allocateNormal(PooledByteBuf<T> buf, int reqCapacity, int normCapacity) {
         if (q050.allocate(buf, reqCapacity, normCapacity) || q025.allocate(buf, reqCapacity, normCapacity) ||
             q000.allocate(buf, reqCapacity, normCapacity) || qInit.allocate(buf, reqCapacity, normCapacity) ||
             q075.allocate(buf, reqCapacity, normCapacity) || q100.allocate(buf, reqCapacity, normCapacity)) {